Media captionJohn Vine: "The border agency weren't able to tell me the outcomes of analysing information"

There are failings in the way the UK Border Agency uses intelligence to tackle illegal immigration, a report by its independent chief inspector says.

John Vine said intelligence was used inconsistently and the outcome of allegations was not always tracked.

He also warned some staff could be disproportionately targeting some nationalities.

Ministers say the UKBA's "intelligence-led" approach is focusing resources where they were most needed.

'Driving force'

The agency receives about 100,000 pieces of intelligence a year, often reports of people working illegally.

But the report said the agency couldn't say how much of this information led to investigators apprehending illegal workers, or those trying to enter the UK unlawfully.

Using intelligence from a variety of sources, including members of the public, we carried out 1,400 arrests, 330 prosecutions and 260 removalsImmigration minister Damian Green

"There is a real need for the agency to focus more rigorously on the actual outcome of intelligence," said Mr Vine.

"There is insufficient understanding across the agency of the role that intelligence should play and whether or not it is the driving force for meeting objectives.

"The agency should have a clearer idea of how the use of intelligence contributes to preventing and detecting immigration and customs offences."

Mr Vine said the inspection had found examples of the UKBA using intelligence well, such as in some drug seizures. But there were instances where it was not clear what had been achieved.

'Knowledge and experience'

In one case, the UKBA was tipped off that a dozen people were arriving on student visas from Sri Lanka, intending to work illegally. But the agency had no record of whether officers had identified the suspects and what had happened to them.

"Overall, the agency was not able to identify the proportion of allegations that had resulted in people being prevented from entering the UK or which had led to enforcement action," said the report.

"In the absence of this data, it makes it very difficult to judge how significant allegations are to the effective identification of offenders, the level of resources that should be devoted to handling allegations and the most effective systems to facilitate this."

At some ports, frontline staff were using different methods to identify suspects - but there was no evidence that the range of techniques were being evaluated to see if they led to more legitimate stops.

This meant it was not clear whether some staff were using "knowledge and experience" to identify suspects or simply discriminating on basis of nationality or ethnicity.

The agency is currently cutting 20% of its spending. Mr Vine's report reveals that it is reducing the number of seconded police officers from 220 to 60, replacing them with its own staff.

Andrew Green from campaign group Migration Watch said the report highlighted some serious shortcomings within the agency.

"The ability to remove people who have no right to be in this country is absolutely fundamental to the credibility of the entire immigration system. Remember, we issue something like two million visas a year and if we can't remove those who stay on illegally then we're all wasting our time," he said.

Immigration minister Damian Green said: "Enforcement activity is the cornerstone of our new immigration system and our intelligence-led approach means we are working smarter; focusing resources where they matter the most.

"We have already launched two nationwide campaigns to close bogus colleges, tackle illegal working and reduce sham marriages.

"Using intelligence from a variety of sources, including members of the public, we carried out 1,400 arrests, 330 prosecutions and 260 removals."